1990 Mariner outboard

TrevorB · 26 July 2013, 17:35

trouble getting to the water pump one bolt already sheared won’t take much to shear the others they are really tight

Should I try warming up the casting then removing the bolts ?

If and when they come out should they be replaced with something else like stainless or will this cause erosion problems

Jizm · 26 July 2013, 20:31

Which bolt is it?

TrevorB · 26 July 2013, 20:51

Hi jim it is one of the corner rear bolts, I would go look, but the box is away having a skeg weld done. I removed it by removing what I suspect might be a short shaft to long shaft conversion which. I removed this section with the gear box, but the gear box will need to be removed from this box to get water pump access

The engine is a Mariner Yamaha 40h manual start late 80 early 90's if that helps

Nos4r2 · 26 July 2013, 21:13

Take pics.

Festinghouse · 27 July 2013, 07:48

sheared bolts can be removed if you are any good with a welder, and unless someone can say why not, then id suggest reassembly using copper grease.

TrevorB · 27 July 2013, 10:21

No I am not a welder, I am an electronics engineer, Ok with micro chips, but they come out with less effort (sometimes). I assume you warm up the alloy housing before attempting to remove the other stuck bolts. The sheared bolt needs drilling out ?. There is left hand threaded spiral device ( ease it out out some such name) do they work ?
Thanks for the advice I have not ordered any stainless bolts, but I will buy some copper grease

Nos4r2 · 27 July 2013, 10:45

Don't copper grease them unless you want them to sieze again. Copper on ally causes some rather nasty galvanic corrosion.

Grease them with a GOOD waterproof grease, or use a zinc based anti sieze compound. There is one specifically for marine use, but I can't remember the name. I use Corrosion Block grease, and have never had a problem, where most other greases have failed badly.

Festinghouse · 27 July 2013, 12:40

ive broken so many of those screw extactors that i dont bother with them! instead i put a washer over the remaining thread, then a much larger nut, i then weld the large nut to the broken bolt by filling the nut with weld. let it cool partially then undo with a socket.
the heat travels down the bolt well, and paintwork damage is minimal.

TrevorB · 28 July 2013, 09:04

Quote:

Originally Posted by Festinghouse

ive broken so many of those screw extactors that i dont bother with them! instead i put a washer over the remaining thread, then a much larger nut, i then weld the large nut to the broken bolt by filling the nut with weld. let it cool partially then undo with a socket.
the heat travels down the bolt well, and paintwork damage is minimal.

Festinghouse thanks or the advice but it is a bolt sheared off about 10mm below the surface, not a protruding stud, so I assume drilling with a stand drill to to ensure going vertical with the bolt and keep increasing the drill size ???

not that I have a stand drill

Festinghouse · 28 July 2013, 09:21

in that case then yes thats probably your best and only option. you have to be very careful as getting the drill perfectly central is nigh on impossible and so damaging the thread in the casting is very easy to do.

Nos4r2 · 28 July 2013, 09:40

Take pics!

If you want decent advice, show people the problem.

(Not saying any advice is bad so far, but it's impossible to give specific advice without pics...)

paddlers · 28 July 2013, 10:12

I'd consider taking it to a proper engineer who has all the gear to get that out rather than messing about with usual poor quality extractors that are generally available !!
Might seem expensive but when you consider the alternatives it could work out as money well spent.
Good luck with it.

TrevorB · 05 August 2013, 10:57

Gear box removed complete with the section above might be a short to long shaft conversion box ?

The local welding shop have repaired the skeg and removed the bolts connecting the gear box to conversion box
I sheared one they sheared two more and had to weld nuts on two bolts to get them out

They have drilled out the bolts that sheared of inside and re tapped the threads
Cost £65 The local boatyard wanted £250 to £300 just to repair the skeg

Now re assembled and gearbox topped up need to run it and recheck the gear box make sure they have not damaged prop seals

Thanks for all the help from all the above

anyone have a Yamaha 40h manual about 1990 vintage